Post-traumatic stress disorder (PTSD) is a pathological anxiety that occurs when an individual experiences or witnesses severe trauma that constitutes a threat to his/her physical integrity or that of another person. The individual initially responds with intense fear, a sense of hopelessness, or horror; later he or she may re-experience the event, with resultant symptoms of numbness, avoidance, hypervigilance and hyperarousal. These symptoms lead to clinically significant distress and/or functional impairment.
Traditionally, medical approaches to PTSD have relied upon pharmacological agents with heavy utilization of selective serotonin reuptake inhibitors (SSRIs), which affect the levels of serotonin in the brain. The challenge is that although these medications have relatively low rates of significant side-effects, only 50% to 60% of patients enjoy any appreciable reduction in symptoms. Further, SSRIs can take up to eight weeks to achieve a clinical response, and are associated with a high drop-out rate. Other approaches include light therapy and exposure therapy, but the efficacy of each depends upon treatment duration and compliance.